1. Field of the Invention
The present invention relates to a method of forming a local mobility domain (LMD) and a local mobility agent (LMA). More particularly, the present invention relates to a method of forming an LMD and an LMA based on Mobile IP and an apparatus thereof.
2. Description of the Related Art
As the Internet has grown and as users have become more interested in mobile Internet access, the number of available IP addresses for network devices is decreasing. With drawbacks of the existing IPv4 becoming more evident, a new protocol, known as IPv6, has been defined.
Conventional mobile terminals, having access to the Internet under IPv6, each have a fixed home address and a home agent (HA). When the mobile terminal moves to a network other than the home network, the mobile terminal receives a care-of-address (COA), which represents a new location of the mobile terminal.
Referring to a conventional system shown in FIGS. 1 and 2, a mobile node (MN) reports the care-of-address to a home agent. Thereafter, data targeting the MN is input to the home network of the MN where it is received by the HA and transferred to the COA for the MN. In the following figures, the abbreviations AR, CN, MN, and BU denote an access router, a correspondent node, a mobile node, and a binding update, respectively.
In the case that the home network (HOME N/W) is far from a present network, such as the foreign networks (FOREIGN N/W) indicated in FIGS. 1 and 2, it is inconvenient to register every movement of the MN to the HA. For such cases, each network is divided into LMDs, each domain containing an LMA, which operates as a local HA. In an LMD, the MN receives a regional care-of-address (RCOA) and a local care-of-address (LCOA). In this case, the RCOA represents the location of the LMA in the LMD, and the LCOA represents the present location of the MN.
With reference to FIGS. 3 through 6, an MN registers a present location and the location of a present LMA to a home LMA and the HA, respectively. When data targeting the MN is input to the home network, the HA sends the data to the present LMA of the MN and the present LMA transfers the data to the MN, as shown in FIG. 4. If the MN moves within the LMD, the MN registers a new location to the home LMA, as shown in FIG. 5. The data transferred to the MN is transferred through the HA, the new LMA, and a new access router (AR), as shown in FIG. 6.
According to a conventional protocol, a network manager establishes the LMD and LMA. However, since it is difficult to correct the LMD according to changes of the networks, the LMA may become the point of failure for the entire network.